Hydrothermally synthesized MoS2 NFs toward efficient supercapacitor and fast photocatalytic degradation of MB

Abstract

MoS₂ stands out as a distinctive material, owing to its two-dimensional structure, with promising potential across various domains notably in energy storage and photocatalysis. In the present work, a pH-assisted hydrothermal approach (one step) has been utilized to synthesize MoS₂ nanoflowers (NFs) using ammonium molybdate and thiourea. Characterization of the prepared MoS₂ NFs was conducted using XRD, FESEM, HRTEM, FTIR, Raman, UV–Vis, PL, BET and XPS techniques. XRD analysis reveals the hexagonal structure of the prepared NFs, while SEM & TEM images confirm the flower-like morphology consisting of many thin petals. Band gap energy determined through the absorption spectrum is 1.9 eV. Notably, the PL spectrum exhibits a strong and broad peak at 688 nm attributed to band-to-band transition indicating multilayer formation of MoS₂ NFs, which is further confirmed by Raman spectroscopy. XPS also confirms the formation of MoS₂ showing Mo⁺⁴ and S⁻² valance states. The specific surface area of MoS₂ NFs is found to be 108.446 m² g⁻¹ that is very high compared to similar materials. Electrochemical properties of MoS₂ NFs were also investigated showing a specific capacitance of 761 F g⁻¹ at 4 A g⁻¹ with an energy density of 21 Wh kg⁻¹ and a power density of 886 Wkg⁻¹ for the MoS₂ NFs-based electrode. Moreover, photocatalytic degradation of MB using MoS₂ NFs at different weight contents (10, 15, 20 and 25 mg) was explored demonstrating highest 97% degradation of MB within 90 min with 20 mg photocatalyst loading along with 0.04 min⁻¹ reaction rate. It also shows good reusability for four consecutive cycles. Furthermore, photodegradation mechanism has also been explored.